There's a significant amount on Cairo, but this is indeed mostly the method JIT.
How do you measure the slowness, anyway? The animation looks less smooth in Fx to me, but it's hard to tell. I tried JM+TI and I couldn't really tell if that was different, either. But I'd like to know.
I wonder when the site decided to add that advice -- maybe before FF4 came out? This could be an evangelism issue.
If you click on "Graphics" and then try to scroll down and up, the UI feels laggy in Firefox Aurora. In Chrome 15 it works well.
The code of the URL seems to have changed. The bug is no longer reproducible.
Their new website is http://www.vvvvjs.com. They don't suggest Chrome over Firefox anymore (or at least, I couldn't find the suggestion anywhere).
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